The Interior of the Earth 



volcanic action and earthquakes. The Scan- 

 dinavian peninsula and Canada have for centuries 

 been undergoing slow variations in level which 

 were manifest as early as the end of the glacial 

 period. We do not mention the movements 

 of this primitive epoch, because a perfectly 

 reasonable theory attributes them simply 

 to the expansion of the ground due to the 

 rise of temperature which followed the 

 glacial period. We must rely on more recent 

 documents. 



As early as 1702 it occurred to the physicist 

 Hjarne to have reference marks cut on the rocks 

 lining the Swedish coast. Linnaeus and Celsius 

 made other marks in 1728 on a cliff of the island 

 of Loeffgrund, and already in 1748 they observed 

 an apparent fall of the sea level, that is to say, 

 an actual rise of the land, seven inches in height. 

 In 1849 the vertical emergence had grown to 

 three feet six inches. While the ground is 

 rising in the neighbourhood of the Gulf of 

 Bothnia, the southern extremity of Sweden is 

 instead sinking slowly into the sea; the mean 

 level of the ground has sunk five feet since 

 Linnaeus made his observations, and several 



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